奶牛体型主要性状的主成分分析

奶牛体型的线性评定方法是本世纪80年代在奶牛遗传改良中出现的一项新技术。奶牛体型线性评定的主要性状有15项,次要性状有14项之多,由此得到的数据资料累计起来就十分可观。如何时这些原始资料统计分析处理,从中提取出有价值的信息显得很重要。本文拟对奶牛体型线性评定的15个主要性状进行主成分分析处理,推导如何将这些性状转化为较少的指标,这些新指标既彼此互不相关、又能综合反映原来多个性状的信息,是原来多个信息的线性组合。从而利用这些较少的新指标就可方便地进行其他的统计分析。一、材料与方法数据取自于奶牛体型线性评定课题组五年中评定的北京市2649头成乳牛资料。评定的15个主要性     

用改进伽玛曲线预测西门塔尔牛产奶量的研究

伽玛曲线公式由伍德(Wood)首先提出(1967)用于乳牛、蛋鸡的产奶与产蛋性能评定。现已证明乳牛泌乳曲线属于伽玛生物曲线,并且其方法已在许多国家广泛应用。伽玛曲线可利用泌乳早期性状预测乳牛305天产奶量,这对于早期评定、早期选择、增加后裔鉴定女儿数以及指导饲养管理等,都具有较高的实用价值。     

应用改进的同龄比较(MCC)法原理选择乳用种公牛的探讨

<正> 乳用种公牛的评定和选择对乳牛的遗传改良至关重要。近年来,随着冷冻精液技术水平的提高,乳牛的人工授精已基本上普及,一方面为优秀种公牛的充分利用提供了可行性;另一方面,由于种公牛的利用年限增长,其女儿的分布广,因而增加了评定和选择种公牛的难度。在公牛的评定中,如何正确合理地消除非遗传因素对公牛女儿产奶记录的影响就成了乳牛     

泌乳牛的饲养技术

泌乳牛的一个泌乳期大体上可分为泌乳初期、泌乳盛期、泌乳中后期和干乳期。由于乳牛各阶段生理条件、生产性能、采食特点等不同,对饲养管理的要求也不同。目前乳牛的饲养方法主要有常规饲养法、预支饲养法和挑战饲养法。1常规饲养法青饲料、粗饲料和副料满足乳牛的维持营养需要,精饲料满足产奶的营养需要,乳牛每产3kg奶喂给1kg混合精料,这种“按奶给料”的饲养方法称为乳牛的常规饲养法。它适合于体况正常的处于泌乳中后期的乳牛。2预支饲养法从母牛产后15～20d开始,在吃足青、粗、副料的前提下,在按奶给料满足维持和泌乳实际营养需要的基…     

泌乳牛的饲养技术

泌乳牛的一个泌乳期大体上可分为泌乳初期、泌乳盛期、泌乳中后期和干乳期。由于乳牛各阶段生条件、生产性能、采食特点等不同，对饲养理的要求也不同。目前乳牛的饲养方法主要有常规饲养法、预支饲养法、预支饲养法和挑战饲养法。１常规饲养法青饲料、粗饲料和副料满足乳牛的维持营养需要，精饲料满足产奶的营养需要，乳牛每产３千克奶喂给１千克混合精料，这种按奶给料的饲养方法称为乳牛的常规饲养法。它适合于体况正常的处于泌乳中后期的乳牛。２预支饲养法从母牛产后１５～２０d开始，在吃足着、粗、副料的前提下，在按奶给料满足维持…     

合理饲喂泌乳奶牛的方法

<正>泌乳牛的泌乳期大体上可分为泌乳初期、泌乳盛期、泌乳中后期和干乳期。由于乳牛各阶段的生活条件、生产性能和采食特点等不同,对饲养管理的要求也不同。1常规饲养法青饲料、精饲料和副料可满足乳牛维持营养的需要,精饲料满足产奶的营养需要,乳牛每产3kg奶应喂给1kg混合精料,这种"按奶给料"的饲养方法称为乳牛的常规饲养法。该种饲养方法     

猪育种进展及其发展趋势

良种是畜牧业增产增效的第一技术要素，是科技转化为生产力的主要载体。纵观世界发达国家畜牧业的发展道路，开始是通过大幅度增加畜禽饲养头数来增加畜禽产品，即数量型发展阶段，以后转入质量型发展阶段，就是通过改进动物品质，提高生产性能，压缩饲养头数来增加畜产品数量。发达国家已经完成了质量型发展阶段，例如美国５０年前每头乳牛１个泌乳期的产乳量只有２０００ｋｇ左右，现在平均达到７５００ｋｇ，养１头乳牛比５０年前养３头乳牛的产乳量还高。所以美国饲养乳牛头数５０年内从２５００万头降至９００万头，产乳量却增加了。由…     

乳牛生殖机能的激发

于1980—81年和1981—82年在苏联一家生产规模为1200头的集体农庄乳牛场,用对机体没有副作用的生物学活性制剂,即初乳配合嗜神经制剂新的斯明和简便的方法,进行了三个激发乳牛生殖机能正常化的试验。试验用乳牛的初乳。挤奶前用温水清洗乳房,并用消毒毛巾擦干,然后用70度酒精棉球常规消毒,第一股奶不用。     

用骨髓穿刺术诊断乳牛白血病

乳牛白血病是乳牛造血系统发生恶性病变的血液肿瘤.对此病的诊断,国内外以往多采用血液学和血清学的诊断方法.血液学的检查主要是外周血的常规检验和计     

奶牛乳房数量性状与产奶量的相关分析

奶牛乳房数量性状与产奶量的相关分析王杏龙，杨章平，徐允令（江苏农学院牧医系扬州２２５００１）前言现代奶牛育种主要从生产性能和体型两方面进行评定。过去对奶牛的体型评定采用描述比较的体型评定方法，由于该方法带有抽象的主观性并与实际有很大距离。因此，近几年...     

Association test between haplotypes and longitudinal traits in complex pedigrees

Evaluating the association of candidate genes with longitudinal traits would be a useful method to study the genetic basis of complex traits. Haplotypes incorporate more information about the underlying polymorphisms than do genotypes for individual SNP, and have been considered as a more informative format of data in association analysis. In this study, we extended the random regression model to allow analysing haplotype effects in a longitudinal framework and then performed a hierarchical Bayesian method to estimate parameter values. We assessed the performance of the proposed approach and demonstrated its validity and power with simulation. The power of our method was also demonstrated by an example of Meishan pigs, in which one haplotype affecting the total number of piglets born was detected using our method, whereas it cannot be detected using the conventional single SNP-based model. Additionally, the model is flexible to be extended to model a complex network of genetic regulation that includes the interactions between different haplotypes and between haplotypes and environments.     

哺乳动物胚胎冷冻保存研究进展

哺乳动物胚胎冷冻保存效果受冷冻保护剂、冷冻方法、解冻方法等多种因素影响,其中冷冻方法是一个关键性因素.目前胚胎冷冻方法主要有常规慢速冷冻法和玻璃化冷冻法两种.常规慢速冷冻法是指利用甘油、乙二醇等做冷冻保护剂通过缓慢降温的方式进行胚胎冷冻;玻璃化冷冻法是指利用高浓度的冷冻保护剂通过快速降温的方式进行胚胎冷冻.与常规慢速冷冻法相比,玻璃化冷冻法简化了操作过程,大大缩短了操作时间,不需昂贵的程序控制冷冻仪.     

Comparison of cardiac function and coronary angiography between conventional pigs and micropigs as measured by multidetector row computed tomography

Pigs are the most likely source animals for cardiac xenotransplantation. However, an appropriate method for estimating the cardiac function of micropigs had not been established. Computed tomography (CT) analysis aimed at estimating cardiac function and assessing the coronary arteries has not been carried out in micropigs. This study determined the feasibility of evaluating cardiac function in a micropig model using multidetector row computed tomography (MDCT) and compared the cardiac function values with those of conventional pigs. The mean age of the conventional pigs and micropigs was approximately 80 days and approximately 360 days, respectively. The mean body weight in the conventional pigs and micropigs was 29.70 ± 0.73 and 34.10 ± 0.98 kg, respectively. Cardiac MDCT detected ejection fractions of 52.93 ± 3.10% and 59.00 ± 5.56% and cardiac outputs of 1.46 ± 0.64 l/min and 1.21 ± 0.24 l/min in conventional pigs and micropigs, respectively. There were no significant differences in cardiac function between conventional pigs and micropigs in the reconstructed CT images. There were also no differences in the coronary angiographic images obtained by MDCT. It is expected that the results of this study will help improve understanding of cardiac function in micropigs. The data presented in this study suggest that MDCT is a feasible method for evaluating cardiac function in micropigs.     

冷冻方法和冷冻保护液对山羊卵母细胞发育的影响

比较了不同冷冻方法和冷冻保护液对山羊卵母细胞冷冻-解冻后体外受精和激活后的发育效果.结果表明,开放式拉长塑料细管(OPS)法的效果好于玻璃化细管法和常规冷冻法;在OPS法中,20%EG 20%DMSO对卵母细胞的冷冻保护效果好于EDFS40,而在玻璃化细管法冷冻中,则是EDFS40好于20%EG 20%DMSO.对于常规冷冻法而言,则是1.5mol/L EG的冷冻效果好于1.5mol/L PROH.     

Canine Haematopoietic Chimerism Analyses by Semiquantitative Fluorescence Detection of Variable Number of Tandem Repeat Polymorphism

Canine models are successfully applied to the study of haematopoietic stem cell transplantation (HSCT). Monitoring of haematopoietic donor/recipient chimerism is of major significance in detecting and quantifying engraftment or graft rejection of the donor-derived haematopoietic cells after transplantation. Radioactive analyses of polymorphic microsatellite markers are commonly used for chimerism analyses. We describe an improved, non-isotopic method that is based on the analysis of microsatellite markers in donor and recipient cells using capillary electrophoresis and fluorescence detection. Artificial mixtures of donor and recipient DNA that were generated from peripheral blood mononuclear cells from dog leukocyte antigen-identical siblings were used to analyse the sensitivity of the assay. DNA from dogs that had received HSCT were also analysed in order to demonstrate the feasibility of the method in vivo. For chimerism analyses, six different microsatellite loci were systematically amplified using fluorescent PCR primer. The fluorescent polymerase chain reaction products were separated by capillary electrophoresis using POP4 on a 310 ABI Prism Genetic Analyzer. After electrophoresis, fluorescence signals were automatically sized and quantified using GeneScan software. The method described provides an accurate assessment of haematopoietic chimerism in the canine model with significantly reduced hands-on time compared to conventional gel electrophoresis.     

A robust method for simultaneous estimation of single gene and polygenic effects in dairy cows using externally estimated breeding values as prior information

The aim of this study was to develop a robust method to estimate single gene and random polygenic animal effects simultaneously in a small field dataset with limited pedigree information. The new method was based on a Bayesian approach using additional prior information on the distribution of externally estimated breeding values. The field dataset consisted of 40 269 test‐day records for milk performance traits for 1455 genotyped dairy cows for the 11 bp‐deletion in the coding sequence of the myostatin gene. For all traits, estimated additive effects of the favoured wild‐type allele (‘+’ allele) were smaller when applying the new method in comparison with the application of a conventional mixed inheritance test‐day model. Dominance effects of the myostatin gene showed the same behaviour but were generally lower than additive effects. Robustness of methods was tested using a data‐splitting technique, based on the correlation of estimated breeding values from two samples, with one‐half of the data eliminated randomly from the first sample and the remaining data eliminated from the second sample. Results for 100 replicates showed that the correlation between split datasets when prior information included was higher than the conventional method. The new method led to more robust estimations for genetic effects and therefore has potential for use when only a small number of genotyped animals with field data and limited pedigree information are available.     

地理空间分层抽样对大尺度草地估产精度的改善—-以低地草甸为例

为优化天然草地监测策略,提高样本点的地域空间代表性和分层估产模型的稳定性,改善全国天然草地地上生物量的估测精度,以低地草甸草原为研究对象,结合地面采样数据和MODIS-NDVI数据,根据统计学的分层抽样方法和全国草地资源区划原理为理论依据,通过分层效率检验、总体平均值误差对比验证和模型分析等方法,以低地草甸为例进行分析。结果表明:各分层区域的分层效率都大于1;采用分层抽样方法相对于简单随机抽样方法地面采样样本的总体平均值精度提高9.672%,模型的估产精度提高13.827%。从而,验证了某一类型草地的区域分层抽样方法比简单随机抽样方法更可取。     

A new method of measuring the transepidermal water loss (TEWL) of dog skin

Human skin barrier function is evaluated by measuring transepidermal water loss (TEWL). However, this conventional method has not been applied to assess canine skin barrier function because the equipment is not suitable for dogs due to the effects of air turbulence resulting from movement of the subject and vapor from the subject's hair coat. The TEWL analyzer CC-01 was developed as a closed-chamber method device; this means that instead of using the open-chamber method, it has a ventilated chamber that uses dry air. TEWL values measured by CC-01 show less variability than those measured by the conventional method. An ambient temperature of 20-26 degrees C is optimal for measurement with the CC-01, and humidity affects the length of measurement but not the values. The CC-01 may be more reliable for measurement of TEWL than the conventional methods and may give new insights in the evaluation of skin barrier function in dogs.     

Comparison of DNA probe test and cultivation methods for detection of Mycobacterium avium subsp paratuberculosis in caprine and ovine faeces

OBJECTIVE: To compare a DNA probe test with two cultivation methods for the detection of Mycobacterium avium subsp paratuberculosis in goat and sheep faeces. DESIGN: Comparison of the results of the three methods with histological examination as the reference standard. PROCEDURE: Faecal specimens were obtained from goats and sheep originating from flocks known to be affected with paratuberculosis and tested for Mycobacterium avium subsp paratuberculosis with a DNA probe test and two cultivation methods (old conventional culture and new double incubation method in Herrold's and Lowenstein-Jensen medium). RESULTS: In goats, the sensitivity of the various tests were for the DNA probe test 17.2%, for the double incubation culture method 25.4% and for the old conventional culture method 22.8% using the histopathological results as reference. In sheep the sensitivity of the various tests were for the DNA probe test 13.2%, for the double incubation culture method 8.8% and for the old conventional culture method 5.9% using the histopathological results as reference. The specificity of the above tests was 100% in goats and sheep and the specificity of the double incubation culture method in goats was 91%. CONCLUSIONS: The DNA probe test is a rapid and specific test that could be used in a control program if the sensitivity of the test were improved and possibly in combination with another test.     

DENTAL RADIOGRAPHY IN THE DOG WITH A CONVENTIONAL X-RAY DEVICE

This study describes a method of using a conventional x-ray device and film-positioning system for dental radiography in dogs. This system is economical, safe and results in high quality dental radiographs.